[#199] [#198] update http client library, fix issues with internal login retries

Gopkg.lock

@@ -39,7 +39,7 @@
   branch = "master"
   name = "github.com/coryb/oreo"
   packages = ["."]
-  revision = "4a1bd6c0c5ea9f07efacc1cefe4d6d38e469a954"
+  revision = "efd7a2135270bc44f64af39446c7226057e6953d"
 
 [[projects]]
   name = "github.com/davecgh/go-spew"
@@ -107,12 +107,6 @@
   revision = "792786c7400a136282c1664665ae0a8db921c6c2"
   version = "v1.0.0"
 
-[[projects]]
-  name = "github.com/sethgrid/pester"
-  packages = ["."]
-  revision = "03e26c9abbbf5accb8349790bf9f41bde09d72c3"
-  version = "1.0.0"
-
 [[projects]]
   name = "github.com/stretchr/testify"
   packages = ["assert"]

vendor/github.com/coryb/oreo/oreo.go

@@ -15,7 +15,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/sethgrid/pester"
 	flock "github.com/theckman/go-flock"
 )
 
@@ -33,7 +32,10 @@ type PreRequestCallback func(*http.Request) (*http.Request, error)
 type PostRequestCallback func(*http.Request, *http.Response) (*http.Response, error)
 
 type Client struct {
-	pester.Client
+	http.Client
+	backoff    BackoffStrategy
+	maxRetries int
+
 	preCallbacks  []PreRequestCallback
 	postCallbacks []PostRequestCallback
 
@@ -47,7 +49,7 @@ type Client struct {
 
 func New() *Client {
 	return &Client{
-		Client:               *pester.New(),
+		maxRetries:           3,
 		handlingPostCallback: false,
 		preCallbacks:         []PreRequestCallback{},
 		postCallbacks:        []PostRequestCallback{},
@@ -61,8 +63,6 @@ func (c *Client) WithCookieFile(file string) *Client {
 	if cp.Jar != nil {
 		cp.Jar = nil
 	}
-	// need to reset cached http client with embedded jar
-	cp.Client.EmbedHTTPClient(nil)
 	return &cp
 }
 
@@ -70,50 +70,33 @@ func (c *Client) WithRetries(retries int) *Client {
 	cp := *c
 	// pester MaxRetries is really a MaxAttempts, so if you
 	// want 2 retries that means 3 attempts
-	cp.MaxRetries = retries + 1
+	cp.maxRetries = retries + 1
 	return &cp
 }
 
 func (c *Client) WithTimeout(duration time.Duration) *Client {
 	cp := *c
 	cp.Timeout = duration
-	// need to reset cached http client with embedded timeout
-	cp.Client.EmbedHTTPClient(nil)
 	return &cp
 }
 
 type BackoffStrategy int
 
 const (
-	CONSTANT_BACKOFF           BackoffStrategy = iota
-	EXPONENTIAL_BACKOFF        BackoffStrategy = iota
-	EXPONENTIAL_JITTER_BACKOFF BackoffStrategy = iota
-	LINEAR_BACKOFF             BackoffStrategy = iota
-	LINEAR_JITTER_BACKOFF      BackoffStrategy = iota
+	CONSTANT_BACKOFF BackoffStrategy = iota
+	LINEAR_BACKOFF   BackoffStrategy = iota
+	NO_BACKOFF       BackoffStrategy = iota
 )
 
 func (c *Client) WithBackoff(backoff BackoffStrategy) *Client {
 	cp := *c
-	switch backoff {
-	case CONSTANT_BACKOFF:
-		cp.Backoff = pester.DefaultBackoff
-	case EXPONENTIAL_BACKOFF:
-		cp.Backoff = pester.ExponentialBackoff
-	case EXPONENTIAL_JITTER_BACKOFF:
-		cp.Backoff = pester.ExponentialJitterBackoff
-	case LINEAR_BACKOFF:
-		cp.Backoff = pester.LinearBackoff
-	case LINEAR_JITTER_BACKOFF:
-		cp.Backoff = pester.LinearJitterBackoff
-	}
+	cp.backoff = backoff
 	return &cp
 }
 
 func (c *Client) WithTransport(transport http.RoundTripper) *Client {
 	cp := *c
 	cp.Transport = transport
-	// need to reset cached http client with embedded tranport
-	cp.Client.EmbedHTTPClient(nil)
 	return &cp
 }
 
@@ -152,8 +135,6 @@ func (c *Client) WithoutCallbacks() *Client {
 func (c *Client) WithCheckRedirect(checkFunc func(*http.Request, []*http.Request) error) *Client {
 	cp := *c
 	cp.CheckRedirect = checkFunc
-	// need to reset cached http client with embedded CheckRedirect
-	cp.Client.EmbedHTTPClient(nil)
 	return &cp
 }
 
@@ -323,6 +304,14 @@ func (c *Client) loadCookies() ([]*http.Cookie, error) {
 	return cookies, nil
 }
 
+type bytesReaderCloser struct {
+	bytes.Reader
+}
+
+func (b *bytesReaderCloser) Close() error {
+	return nil
+}
+
 func (c *Client) Do(req *http.Request) (resp *http.Response, err error) {
 	for _, cb := range c.preCallbacks {
 		req, err = cb(req)
@@ -338,50 +327,85 @@ func (c *Client) Do(req *http.Request) (resp *http.Response, err error) {
 
 	// Callback may want to resubmit the request, so we
 	// will need to rewind (Seek) the Reader back to start.
-	if len(c.postCallbacks) > 0 && !c.handlingPostCallback && req.Body != nil {
+	if (c.maxRetries != 0 || (c.traceRequestBody || len(c.postCallbacks) > 0)) && req.Body != nil {
 		bites, err := ioutil.ReadAll(req.Body)
 		if err != nil {
 			return nil, err
 		}
-		req.Body = ioutil.NopCloser(bytes.NewReader(bites))
+		reader := bytes.NewReader(bites)
+		req.Body = &bytesReaderCloser{*reader}
 	}
 
-	c.log.Printf("%s %s", req.Method, req.URL.String())
-	resp, err = c.Client.Do(req)
-	if err != nil {
-		if c.traceRequestBody {
-			out, _ := httputil.DumpRequest(req, true)
-			c.log.Printf("Request: %s", out)
+	attempt := 1
+	for {
+		resp, err = c.Client.Do(req)
+		if err != nil {
+			if c.traceRequestBody {
+				rewindRequest(req)
+				out, _ := httputil.DumpRequestOut(req, true)
+				c.log.Printf("Request %d: %s", attempt, out)
+			}
+		} else {
+			// we log this after the request is made because http.send
+			// will modify the request to append cookies, so to see the
+			// cookies sent we need to log post-send.
+			if c.traceRequestBody {
+				rewindRequest(req)
+				out, _ := httputil.DumpRequestOut(req, true)
+				c.log.Printf("Request %d: %s", attempt, out)
+			}
+
+			if c.traceResponseBody {
+				out, _ := httputil.DumpResponse(resp, true)
+				c.log.Printf("Response %d: %s", attempt, out)
+			}
 		}
 
+		if err != nil || resp.StatusCode >= 500 {
+			if c.maxRetries < 0 || c.maxRetries < attempt+1 {
+				break
+			}
+
+			var idle time.Duration
+			if c.backoff == CONSTANT_BACKOFF {
+				idle = time.Duration(1 * time.Second)
+			} else if c.backoff == LINEAR_BACKOFF {
+				idle = time.Duration(attempt) * time.Second
+			}
+
+			if err != nil {
+				c.log.Printf("Attempt %d error: %s, retry in %s", attempt, err, idle)
+			} else {
+				c.log.Printf("Attempt %d failed: %s, retry in %s", attempt, resp.Status, idle)
+			}
+
+			select {
+			case <-req.Context().Done():
+				c.log.Printf("Request Context timeout after attempt %d", attempt)
+				return
+			case <-time.After(idle):
+			}
+
+			// need to reset body for the retry
+			rewindRequest(req)
+
+			attempt++
+			continue
+		}
+		break
+	}
+
+	if err != nil {
 		return nil, err
 	}
 
-	// we log this after the request is made because http.send
-	// will modify the request to append cookies, so to see the
-	// cookies sent we need to log post-send.
-	if c.traceRequestBody {
-		out, _ := httputil.DumpRequest(req, true)
-		c.log.Printf("Request: %s", out)
-	}
-
-	if c.traceResponseBody {
-		out, _ := httputil.DumpResponse(resp, true)
-		c.log.Printf("Response: %s", out)
-	}
-
 	err = c.saveCookies(resp)
 	if err != nil {
 		return resp, err
 	}
 
 	if len(c.postCallbacks) > 0 && !c.handlingPostCallback {
-		if req.Body != nil {
-			rs, ok := req.Body.(io.ReadSeeker)
-			if ok {
-				rs.Seek(0, 0)
-			}
-		}
+		rewindRequest(req)
 		c.handlingPostCallback = true
 		defer func() {
 			c.handlingPostCallback = false
@@ -397,6 +421,14 @@ func (c *Client) Do(req *http.Request) (resp *http.Response, err error) {
 	return resp, err
 }
 
+func rewindRequest(req *http.Request) {
+	if req.Body != nil {
+		if rs, ok := req.Body.(io.ReadSeeker); ok {
+			rs.Seek(0, 0)
+		}
+	}
+}
+
 func (c *Client) Get(urlStr string) (resp *http.Response, err error) {
 	parsed, err := url.Parse(urlStr)
 	if err != nil {

vendor/github.com/sethgrid/pester/LICENSE.md

@@ -1,21 +0,0 @@
-MIT License
-
-Copyright (c) SendGrid 2016 
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.

vendor/github.com/sethgrid/pester/pester.go

@@ -1,464 +0,0 @@
-// Package pester provides additional resiliency over the standard http client methods by
-// allowing you to control concurrency, retries, and a backoff strategy.
-package pester
-
-import (
-	"bytes"
-	"errors"
-	"fmt"
-	"io"
-	"io/ioutil"
-	"math/rand"
-	"net/http"
-	"net/url"
-	"sync"
-	"time"
-)
-
-//ErrUnexpectedMethod occurs when an http.Client method is unable to be mapped from a calling method in the pester client
-var ErrUnexpectedMethod = errors.New("unexpected client method, must be one of Do, Get, Head, Post, or PostFrom")
-
-// ErrReadingBody happens when we cannot read the body bytes
-var ErrReadingBody = errors.New("error reading body")
-
-// ErrReadingRequestBody happens when we cannot read the request body bytes
-var ErrReadingRequestBody = errors.New("error reading request body")
-
-// Client wraps the http client and exposes all the functionality of the http.Client.
-// Additionally, Client provides pester specific values for handling resiliency.
-type Client struct {
-	// wrap it to provide access to http built ins
-	hc *http.Client
-
-	Transport     http.RoundTripper
-	CheckRedirect func(req *http.Request, via []*http.Request) error
-	Jar           http.CookieJar
-	Timeout       time.Duration
-
-	// pester specific
-	Concurrency int
-	MaxRetries  int
-	Backoff     BackoffStrategy
-	KeepLog     bool
-	LogHook     LogHook
-
-	SuccessReqNum   int
-	SuccessRetryNum int
-
-	wg *sync.WaitGroup
-
-	sync.Mutex
-	ErrLog         []ErrEntry
-	RetryOnHTTP429 bool
-}
-
-// ErrEntry is used to provide the LogString() data and is populated
-// each time an error happens if KeepLog is set.
-// ErrEntry.Retry is deprecated in favor of ErrEntry.Attempt
-type ErrEntry struct {
-	Time    time.Time
-	Method  string
-	URL     string
-	Verb    string
-	Request int
-	Retry   int
-	Attempt int
-	Err     error
-}
-
-// result simplifies the channel communication for concurrent request handling
-type result struct {
-	resp  *http.Response
-	err   error
-	req   int
-	retry int
-}
-
-// params represents all the params needed to run http client calls and pester errors
-type params struct {
-	method   string
-	verb     string
-	req      *http.Request
-	url      string
-	bodyType string
-	body     io.Reader
-	data     url.Values
-}
-
-var random *rand.Rand
-
-func init() {
-	random = rand.New(rand.NewSource(time.Now().UnixNano()))
-}
-
-// New constructs a new DefaultClient with sensible default values
-func New() *Client {
-	return &Client{
-		Concurrency:    DefaultClient.Concurrency,
-		MaxRetries:     DefaultClient.MaxRetries,
-		Backoff:        DefaultClient.Backoff,
-		ErrLog:         DefaultClient.ErrLog,
-		wg:             &sync.WaitGroup{},
-		RetryOnHTTP429: false,
-	}
-}
-
-// NewExtendedClient allows you to pass in an http.Client that is previously set up
-// and extends it to have Pester's features of concurrency and retries.
-func NewExtendedClient(hc *http.Client) *Client {
-	c := New()
-	c.hc = hc
-	return c
-}
-
-// LogHook is used to log attempts as they happen. This function is never called,
-// however, if KeepLog is set to true.
-type LogHook func(e ErrEntry)
-
-// BackoffStrategy is used to determine how long a retry request should wait until attempted
-type BackoffStrategy func(retry int) time.Duration
-
-// DefaultClient provides sensible defaults
-var DefaultClient = &Client{Concurrency: 1, MaxRetries: 3, Backoff: DefaultBackoff, ErrLog: []ErrEntry{}}
-
-// DefaultBackoff always returns 1 second
-func DefaultBackoff(_ int) time.Duration {
-	return 1 * time.Second
-}
-
-// ExponentialBackoff returns ever increasing backoffs by a power of 2
-func ExponentialBackoff(i int) time.Duration {
-	return time.Duration(1<<uint(i)) * time.Second
-}
-
-// ExponentialJitterBackoff returns ever increasing backoffs by a power of 2
-// with +/- 0-33% to prevent sychronized reuqests.
-func ExponentialJitterBackoff(i int) time.Duration {
-	return jitter(int(1 << uint(i)))
-}
-
-// LinearBackoff returns increasing durations, each a second longer than the last
-func LinearBackoff(i int) time.Duration {
-	return time.Duration(i) * time.Second
-}
-
-// LinearJitterBackoff returns increasing durations, each a second longer than the last
-// with +/- 0-33% to prevent sychronized reuqests.
-func LinearJitterBackoff(i int) time.Duration {
-	return jitter(i)
-}
-
-// jitter keeps the +/- 0-33% logic in one place
-func jitter(i int) time.Duration {
-	ms := i * 1000
-
-	maxJitter := ms / 3
-
-	// ms ± rand
-	ms += random.Intn(2*maxJitter) - maxJitter
-
-	// a jitter of 0 messes up the time.Tick chan
-	if ms <= 0 {
-		ms = 1
-	}
-
-	return time.Duration(ms) * time.Millisecond
-}
-
-// Wait blocks until all pester requests have returned
-// Probably not that useful outside of testing.
-func (c *Client) Wait() {
-	c.wg.Wait()
-}
-
-// pester provides all the logic of retries, concurrency, backoff, and logging
-func (c *Client) pester(p params) (*http.Response, error) {
-	resultCh := make(chan result)
-	multiplexCh := make(chan result)
-	finishCh := make(chan struct{})
-
-	// track all requests that go out so we can close the late listener routine that closes late incoming response bodies
-	totalSentRequests := &sync.WaitGroup{}
-	totalSentRequests.Add(1)
-	defer totalSentRequests.Done()
-	allRequestsBackCh := make(chan struct{})
-	go func() {
-		totalSentRequests.Wait()
-		close(allRequestsBackCh)
-	}()
-
-	// GET calls should be idempotent and can make use
-	// of concurrency. Other verbs can mutate and should not
-	// make use of the concurrency feature
-	concurrency := c.Concurrency
-	if p.verb != "GET" {
-		concurrency = 1
-	}
-
-	c.Lock()
-	if c.hc == nil {
-		c.hc = &http.Client{}
-		c.hc.Transport = c.Transport
-		c.hc.CheckRedirect = c.CheckRedirect
-		c.hc.Jar = c.Jar
-		c.hc.Timeout = c.Timeout
-	}
-	c.Unlock()
-
-	// re-create the http client so we can leverage the std lib
-	httpClient := http.Client{
-		Transport:     c.hc.Transport,
-		CheckRedirect: c.hc.CheckRedirect,
-		Jar:           c.hc.Jar,
-		Timeout:       c.hc.Timeout,
-	}
-
-	// if we have a request body, we need to save it for later
-	var originalRequestBody []byte
-	var originalBody []byte
-	var err error
-	if p.req != nil && p.req.Body != nil {
-		originalRequestBody, err = ioutil.ReadAll(p.req.Body)
-		if err != nil {
-			return nil, ErrReadingRequestBody
-		}
-		p.req.Body.Close()
-	}
-	if p.body != nil {
-		originalBody, err = ioutil.ReadAll(p.body)
-		if err != nil {
-			return nil, ErrReadingBody
-		}
-	}
-
-	AttemptLimit := c.MaxRetries
-	if AttemptLimit <= 0 {
-		AttemptLimit = 1
-	}
-
-	for req := 0; req < concurrency; req++ {
-		c.wg.Add(1)
-		totalSentRequests.Add(1)
-		go func(n int, p params) {
-			defer c.wg.Done()
-			defer totalSentRequests.Done()
-
-			var err error
-			for i := 1; i <= AttemptLimit; i++ {
-				c.wg.Add(1)
-				defer c.wg.Done()
-				select {
-				case <-finishCh:
-					return
-				default:
-				}
-
-				// rehydrate the body (it is drained each read)
-				if len(originalRequestBody) > 0 {
-					p.req.Body = ioutil.NopCloser(bytes.NewBuffer(originalRequestBody))
-				}
-				if len(originalBody) > 0 {
-					p.body = bytes.NewBuffer(originalBody)
-				}
-
-				var resp *http.Response
-				// route the calls
-				switch p.method {
-				case "Do":
-					resp, err = httpClient.Do(p.req)
-				case "Get":
-					resp, err = httpClient.Get(p.url)
-				case "Head":
-					resp, err = httpClient.Head(p.url)
-				case "Post":
-					resp, err = httpClient.Post(p.url, p.bodyType, p.body)
-				case "PostForm":
-					resp, err = httpClient.PostForm(p.url, p.data)
-				default:
-					err = ErrUnexpectedMethod
-				}
-
-				// Early return if we have a valid result
-				// Only retry (ie, continue the loop) on 5xx status codes and 429
-
-				if err == nil && resp.StatusCode < 500 && (resp.StatusCode != 429 || (resp.StatusCode == 429 && !c.RetryOnHTTP429)) {
-					multiplexCh <- result{resp: resp, err: err, req: n, retry: i}
-					return
-				}
-
-				c.log(ErrEntry{
-					Time:    time.Now(),
-					Method:  p.method,
-					Verb:    p.verb,
-					URL:     p.url,
-					Request: n,
-					Retry:   i + 1, // would remove, but would break backward compatibility
-					Attempt: i,
-					Err:     err,
-				})
-
-				// if it is the last iteration, grab the result (which is an error at this point)
-				if i == AttemptLimit {
-					multiplexCh <- result{resp: resp, err: err}
-					return
-				}
-
-				//If the request has been cancelled, skip retries
-				if p.req != nil {
-					ctx := p.req.Context()
-					select {
-					case <-ctx.Done():
-						multiplexCh <- result{resp: resp, err: ctx.Err()}
-						return
-					default:
-					}
-				}
-
-				// if we are retrying, we should close this response body to free the fd
-				if resp != nil {
-					resp.Body.Close()
-				}
-
-				// prevent a 0 from causing the tick to block, pass additional microsecond
-				<-time.After(c.Backoff(i) + 1*time.Microsecond)
-			}
-		}(req, p)
-	}
-
-	// spin off the go routine so it can continually listen in on late results and close the response bodies
-	go func() {
-		gotFirstResult := false
-		for {
-			select {
-			case res := <-multiplexCh:
-				if !gotFirstResult {
-					gotFirstResult = true
-					close(finishCh)
-					resultCh <- res
-				} else if res.resp != nil {
-					// we only return one result to the caller; close all other response bodies that come back
-					// drain the body before close as to not prevent keepalive. see https://gist.github.com/mholt/eba0f2cc96658be0f717
-					io.Copy(ioutil.Discard, res.resp.Body)
-					res.resp.Body.Close()
-				}
-			case <-allRequestsBackCh:
-				// don't leave this goroutine running
-				return
-			}
-		}
-	}()
-
-	res := <-resultCh
-	c.Lock()
-	defer c.Unlock()
-	c.SuccessReqNum = res.req
-	c.SuccessRetryNum = res.retry
-	return res.resp, res.err
-
-}
-
-// LogString provides a string representation of the errors the client has seen
-func (c *Client) LogString() string {
-	c.Lock()
-	defer c.Unlock()
-	var res string
-	for _, e := range c.ErrLog {
-		res += c.FormatError(e)
-	}
-	return res
-}
-
-// Format the Error to human readable string
-func (c *Client) FormatError(e ErrEntry) string {
-	return fmt.Sprintf("%d %s [%s] %s request-%d retry-%d error: %s\n",
-		e.Time.Unix(), e.Method, e.Verb, e.URL, e.Request, e.Retry, e.Err)
-}
-
-// LogErrCount is a helper method used primarily for test validation
-func (c *Client) LogErrCount() int {
-	c.Lock()
-	defer c.Unlock()
-	return len(c.ErrLog)
-}
-
-// EmbedHTTPClient allows you to extend an existing Pester client with an
-// underlying http.Client, such as https://godoc.org/golang.org/x/oauth2/google#DefaultClient
-func (c *Client) EmbedHTTPClient(hc *http.Client) {
-	c.hc = hc
-}
-
-func (c *Client) log(e ErrEntry) {
-	if c.KeepLog {
-		c.Lock()
-		defer c.Unlock()
-		c.ErrLog = append(c.ErrLog, e)
-	} else if c.LogHook != nil {
-		// NOTE: There is a possibility that Log Printing hook slows it down.
-		// but the consumer can always do the Job in a go-routine.
-		c.LogHook(e)
-	}
-}
-
-// Do provides the same functionality as http.Client.Do
-func (c *Client) Do(req *http.Request) (resp *http.Response, err error) {
-	return c.pester(params{method: "Do", req: req, verb: req.Method, url: req.URL.String()})
-}
-
-// Get provides the same functionality as http.Client.Get
-func (c *Client) Get(url string) (resp *http.Response, err error) {
-	return c.pester(params{method: "Get", url: url, verb: "GET"})
-}
-
-// Head provides the same functionality as http.Client.Head
-func (c *Client) Head(url string) (resp *http.Response, err error) {
-	return c.pester(params{method: "Head", url: url, verb: "HEAD"})
-}
-
-// Post provides the same functionality as http.Client.Post
-func (c *Client) Post(url string, bodyType string, body io.Reader) (resp *http.Response, err error) {
-	return c.pester(params{method: "Post", url: url, bodyType: bodyType, body: body, verb: "POST"})
-}
-
-// PostForm provides the same functionality as http.Client.PostForm
-func (c *Client) PostForm(url string, data url.Values) (resp *http.Response, err error) {
-	return c.pester(params{method: "PostForm", url: url, data: data, verb: "POST"})
-}
-
-// set RetryOnHTTP429 for clients,
-func (c *Client) SetRetryOnHTTP429(flag bool) {
-	c.RetryOnHTTP429 = flag
-}
-
-////////////////////////////////////////
-// Provide self-constructing variants //
-////////////////////////////////////////
-
-// Do provides the same functionality as http.Client.Do and creates its own constructor
-func Do(req *http.Request) (resp *http.Response, err error) {
-	c := New()
-	return c.Do(req)
-}
-
-// Get provides the same functionality as http.Client.Get and creates its own constructor
-func Get(url string) (resp *http.Response, err error) {
-	c := New()
-	return c.Get(url)
-}
-
-// Head provides the same functionality as http.Client.Head and creates its own constructor
-func Head(url string) (resp *http.Response, err error) {
-	c := New()
-	return c.Head(url)
-}
-
-// Post provides the same functionality as http.Client.Post and creates its own constructor
-func Post(url string, bodyType string, body io.Reader) (resp *http.Response, err error) {
-	c := New()
-	return c.Post(url, bodyType, body)
-}
-
-// PostForm provides the same functionality as http.Client.PostForm and creates its own constructor
-func PostForm(url string, data url.Values) (resp *http.Response, err error) {
-	c := New()
-	return c.PostForm(url, data)
-}